Generally, solderable elastic electric contact terminals must have high electrical conductivity and high elastic resilience and must be tolerant to high soldering temperature. To this end, solderable electric contact terminals are formed of a metal. Specifically, beryllium copper is widely used for the electric contact terminals because it has high elastic resilience and high electrical conductivity. Specifically, a beryllium copper sheet having a thickness of less than 0.3 mm and a predetermined width is punched into a predetermined shape using a press die and then the punched beryllium copper sheet is heat-treated to form the electric contact terminal having an improved elastic resilience.
However, because of metal characteristic or structure, the electric contact terminals formed of the metal sheet only cannot provide high elasticity at less than a predetermined thickness. To increase the elasticity, the metal sheet must be bent in a predetermined shape. Because the thickness of the electric contact terminal is mostly determined by the bent thickness, the electric contact terminal cannot provide high elasticity at less than a predetermined thickness.
Especially, it is difficult to form a small-sized product having a thickness of less than 2 mm.
Because one press die can form products having an identical shape, additional press dies are needed to form products having different shapes.
In case where the metal sheet is applied to an indium tin oxide (ITO)-coated glass substrate, it may scratch the ITO coating.
Another related art is disclosed in Korean Utility Model Registration No. 2005-0012242, filed by the present applicant. However, a conductive elastic rubber coating layer has an electrical conductivity lower than that of metal. Therefore, an expensive metal powder such as silver (Ag) is used for increasing the electrical conductivity. The use of such an expensive metal powder, however, increases hardness and manufacturing cost. In addition, when the electric contact terminal is formed of the elastic rubber only, the it is difficult to provide an accurate dimension. Furthermore, an additional metal foil must be provided for soldering.